Paadam wrote:

Hi from new guy here! Though I have been playing with computers (and Thinkpad laptops) for almost 25 years since I was in school.

Found a motherboard in friends garage, it was hacked into old IBM PS/2 case. Seems to be late 286 system board (has IDE connectors). 287 socket is empty. Has 5MB of RAM.
But it powered up nicely though complained about CMOS battery being dead? Can't see it on the board, where is it? Did not boot from HD, seemed to forget settings even just by leaving BIOS.

The chip highlighted in green is your CMOS battery / real time clock ( Dallas DS1287/1187 ). This needs to be replaced.

Yeah, did some googling meanwhile and found that out too. Thanks anyway. Not going to replace it but will solder batter to the battery pins.

That thing is really cool. Unlike most 286 motherboards I've seen, this seems to have on-board HDD and FDD controllers - probably because it only has 3 ISA slots. It also has SIMM memory modules witch can come in handy (unlike the 286 boards I've come across witch only have SIP slots). The only things I don't like about it are the fact that it has a Dallas RTC instead of a barrel batt or a con cell batt holder. Also it looks like someone directly soldered the power supply cables to the board - I'd take those off and solder in two AT power connectors.

Yep, cool indeed! 286 machines were the ones that introduced AT-BUS drives (IDE) and VGA. 😀
Dallas RTCs may be time consuming to repair, but they do have an awesome feature: They don't leak.

Btw, these 5MB of memory are good for running Win 3.1 and OS/2 1.x. I have 4MB in my smallest 286 and it is quite speedy..

I have this board too. Dallas is also dead and it won't remember HDD settings. Booting via floppy works fine. Haven't found the time to replace Dallas in over 3 years 🤣

This is the "manual" for it:
http://www.uncreativelabs.de/th99/m/U-Z/33106.htm

Performance wise it's pretty average for 16MHz.